also: オーナシェフ
noun
chef-owner; chef and owner
A restaurant owner who also serves as the head chef. Common in the context of small, high-quality restaurants.
wasei-eigo (Japanese-coined English), from owner chef
あの小さなフレンチレストランのオーナーシェフは、毎日市場で食材を選んでいる。
The chef-owner of that small French restaurant selects ingredients at the market every day.
The chef-owner himself explained the dishes to us.